Fabiana imbricata: the Andean Un-Tomato, a Non-Heath That Looks a lot Like its Cousin Cestrum

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Fabiana imbricata has an appearance much like the upright and shrubby Erica arborea…maybe mixed with an upright form of Rosemary…providing a remarkable texture in the garden.

In gardening and botany one of the first things we learn is that not everything looks as we might expect that it should!  Fabiana imbricata, is a member of the Tomato Family, the Solanaceae, yet, if you don’t look too close, it looks like it might belong to the Ericaceae.  At one time I was planning to take advantage of this similarity as I was attempting evoke a South African feel in part of my garden substituting this for one of the many tender South African heaths as the correct Erica species are either too tender, of borderline hardiness for my conditions or are simply difficult to come by.  It was sharing an area in the garden with Restio capensis, Eucomis spp., Melianthus spp. and others to give an impression of South Africa, not a strict species for species duplication of a community.  I didn’t quite pull it off….I’ve done much the same thing when substituting tropical looking temperate plants for the real thing when evoking a tropical feel.  It’s a matter of manipulation…a sleight of the garden hand.

Its Chilean Home and Garden Merit

Fabiana imbricata is not from South Africa, though it shares Gondwanan roots, and is endemic in Chile, occurring very frequently throughout much of its Andean range.  It is in fact identified as a ‘keystone’ species strongly effecting the composition of its local plant communities.  It can be found growing from well into the dry region of Coquimbo in the north, just south of the huge Atacama Desert, south into the wet Aysen region with its many islands and inlets south of the Lake District or Zona Sur.  The vast area stretches along much of Chile’s length which can be driven, on often tortuous mountain roads, for over 1,700 mi., stretching from the arid city La Serena to the small, rainforest town of Tortel, in the south, a distance almost 500 miles further than the drive from Vancouver, BC to Los Angeles, CA….There are not that many plant species in the world that span a similar latitudinal range with its accompanying climate differences.  As you look for this plant moving from north to south through Chile, the soils and its particular niches change along with the temperature and rainfall.  You are more likely to find this growing exposed in rocky scree in wetter regions to the south, while it tends to be more commonly found on sites more protected from the sun’s intensity and into better soils as you move into the arid and hotter north, more protected from the sun’s tropical intensity.  No surprise there, but overall this is an adaptable plant succeeding in cool rainforest to arid, desert like, conditions.  As would be expected across the more arid portion of its range fire is an important factor in maintaining the plant communities balance, riding it of other competing woody plants  and even aiding it in germination, when followed by ample winter/spring rainfall, though this is obviously not essential for its continuing survival in rainforest areas where fire is much less frequent.   This is a very adaptable species and as we live near the Pacific Coast in the northern hemisphere, which mirrors much of the range of conditions, we should be able to have success with it, if we pay attention to its cold limits.  Those away from the Pacific Coast, especially those with ‘continental’ climates or strong influences from them, will have to pay closer attention.

Flowers, buds and leaves of Fabiana imbricata ‘violacea’,.  Visible here is the small green calyx at its narrow base.  You can also see the short twig structure that project fairly densely from each branch…each twig covered in their tiny leaves.  Its specific epithet, imbricata, refers to the pattern of its small, closely adpressed (held against the stem), scale-like leaves giving it an appearance similar to the Whipcord Hebes, Thuja, Cypressus and ericaceous Calluna spp.From James Gaither at the San Francisco Botanic Garden.  Licensed under the Creative Commons.

There are six other species of Fabiana found in Chile, but none so common and another 8 in other Andean areas, the genus being endemic to the mountain range.

I like this plant.  It’s evergreen, often forming a relatively strong upright structure to 6’+ tall and nearly as wide here.  It is sometimes found taller in its native haunts, but can be bushier on drier, and more hardscrabble sites as well.  The most available form here is one called F. i. ‘violacea’ which tends to be a more upright than the species, has pale lavender flowers and to which some attribute slightly more cold hardiness.

[A friend and fellow gardener with 20 years of experience growing this in western Washington state says that this grows broader and more lax than the literature suggests.]

Fabiana imbricata in Chile grows in soils which are generally shallower, coarser and with less organic content, than we have here…often in quite sandy soil.  In the part of its range, the Lake District, where these receive much more rainfall than we get here, these grow in screes and vary coarse soils.  I suspect our generally deep, rich loams and ample moisture, speed and soften the growth of these in the maritime NW, especially if the gardener is prone to water much in summer.  Soils play a role more directly in a plant’s structure.  Plants have developed various strategies to get what they need from the soils within which they have evolved.  The roots of Fabiana imbriacata are less fibrous than those that evolved in richer, more finely textured soils.  Because coarse, sandy, soils are less nutritive and hold less water, their roots must venture further afield and deeper to obtain what they need.  This has impacts for us both in their abiiity to grow more quickly here with our heavier/richer soils and by being nearly impossible to transplant, because their loose, wide spreading roots tend not to hold soil together when dug.  Consequently they generally die when we attempt to transplant them.  Many woody plants having evolved in poor coarse soils, and grow almost too fast for us, consequently, are more ‘floppy’ and lax here in Willamette Valley loam than is described on tags and in literature.  Be wary of the claims you read on plant labels.  Conditions vary markedly while, because we garden in one place, we tend to speak broadly of what we ‘know’.  Knowledge can be regional.  Fabiana imbricata and plants that evolved under similar conditions,  can also have top growth that puts the entire plant out of ‘balance’ making it more likely to topple and uproot itself, plants like Cupressus spp….Yes, there is such a thing as having too good of growing conditions.  Many plants exhibit this ability to overcome specific less than ideal conditions, that then cause them to be ‘overwhelmed’ when planted out where these nutrients are abundant.  Recall how phosphorous rich fertilizers can be fatal to many species in the Proteaceae.  We need to keep in mind that size and growth rates can vary widely from a writer’s experience.  Soils are every bit as important to a gardener’s success with a given plant, and its ‘fit’ with our designs, as are our climate and weather extremes.

A branch of it appears in the photo at the top of my Blog, a shot I took in my garden about twelve years ago, before we tore out our small front garden and remodeled our house.  It grew there on our south facing bank with other water thrifty plants in the Pacific Northwest like the Iris x pacifica ‘Simply Wild’ its pictured with.  There was a Gevillea x gaudi-chaudi sprawling happily nearby as well.  I planted it later when I reworked ‘Friendship Circle’, next to the Steel Bridge at the north end of Waterfront Park, but it got destroyed there, abused repeatedly as our homeless problem, always a factor in the north end of the Park, increased and someone took to stashing their things in the bed against and on top of it.  It never really had a chance there.  Recently, as mentioned above, I reintroduced it into my back garden to complement my increasing numbers of South African plants, but I may be moving it to the top of my south facing retaining wall to help create a visual barrier as my old cedar fence continues to deteriorate.

Of Flowers and Families

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You can see the little anthers and stigma down inside the fused flower tube and five lobes formed from the corolla recurving out and down. The green calyx tube hugs the base of the flower. Unlike the flower arrangement on either Cestrum or Erica spp. these are attached in loose terminal structures at individual leaf axils.

Now, let’s take a look at these flowers!  I am always looking for connections, similarities in appearance or morphology, between related plants…which doesn’t always help.  Often times it would seem that there are more exceptions to the rules used to classify plants than there are strict ‘rules’ that  plants in given classifications follow.

Fabiana is in the Tomato family, the Solanaceae and shares with all of its member species its production of a wide range of alkaloid metabolites of widely varying potency and effect.  Base on appearance this family would not be the first ‘guess’ of most gardeners.  It doesn’t take a botanist’s eye to see the obvious gross differences in the appearance of the flowers between this and most Solanum spp., the genus that includes the Tomato, Potato and Eggplant.  There are between 1,500-2,000 species within genus Solanum alone and there is work left to do to sort them out.  There are another 97 genera, adding another 700 species, that make up the balance of the family, so expect variety.  Member species are found on every continent but Antarctica with the greatest numbers in South and Central America.

The Solanacea are one of 100 different plant families within the huge group, the Astrids, which includes around 25% of all flowering plants, the Angiosperms, over 80,000 species.  Included among them is the very similarly appearing flowers of genus Erica, but they are only distantly related to Fabiana species.  They are in different sub-families, families and orders.  The difference is somewhat comparable to the genetic ‘distance’ between humans and non-mammalian animal species which share a spinal column.  Nature has achieved structural similarities with different genetics, following different pathways, in similar environments, but often at widely separated locations, isolated on different continents or limited by other physical barriers.

Petunia ‘Starry Night’, a cultivar from over ten years ago, has been replaced by ‘Night Sky’. The lobes are fused the entire length of the floral tube, including out the flaring lobes. Picture from Wikipedia.

Brunfelsia pauciflora, a 6’+ shrub from Brazil with its particular pattern of fused petals. The alkaloids in this are poisonous to most mammals. This level of toxicity is common throughout the genus. Picture from Wikipedia

Calibrachoa are found across much the same region of South America as petunias, from southern Brazil across to Peru and Chile, inhabiting scrub and open grassland. This angle shows the characteristic tube surrounded by its calyx. Wikipedia

Nierembergia frutescens, with its own variations on the Petunioideae pattern. Wikipedia

The Tomato family is broken down into sub-families.  Each sub-family is ‘sister’ to the others having evolved along separate lines from shared ancestors….Does that make sense?  Each sub-family then moves in its own genetic ‘direction’ as evolution progressed producing new species.  As a result of this the sub-families each exhibit a consistency amongst their member species.  Each of the other sub-families will exhibit a similar consistency while the sub-families vary from one to the other.

The Tomato family, shares a lot genetically, while it contains a high degree of variability in its floral structures as, well as in its reproductive characteristics.  Most species members have flowers that possess two carpels or separate chambers in their ovary, but not all.  The fruits are most often berries or capsules, but can sometimes be drupes.  (Fabiana form capsules.  Berries are fleshy fruits containing multiple seeds, like Tomatos.  Drupes, sometimes called ‘stone fruits’, have a single large seed surrounded by a fleshy cover, formed from a single flower.)  Fabiana is within the Petunioideae sub-family, that contains…surprise, surprise, the Petunias…all 13 genera and 160 species of which are limited to South and Central America.  The genera of Petunioideae include, in addition to Fabiana, the other genera,  BrunfelsiaNierembergia, Petunia and Calibrachoa, all of which have contributed popular ornamental species and cultivars to the gardening world.

Flowers in this sub-family typically have 5 petals and sepals, which are fused, most of their length, forming floral tubes that separate into lobes at the ‘mouth’ of the corolla, often quite broadly.  They usually have 4 stamen, two longer, two shorter and always a  superior ovary which is enclosed by the floral tube.  This 5 petal, 5 sepal, superior ovary structure is shared by the vast majority of all 80,000 species of Asterids, the massive clade or genetic lineage that developed separately from the Rosids and other smaller clades within the Angiosperms, so it alone isn’t terribly helpful in keying out the species.  Fabiana species differ from the other genera in their sub-family by having very small lobes at the mouth of their  floral tubes, and unlike the more flat, open. spreading lobes of the rest of the sub-family.  In Fabiana the floral tube is longer than both the calyx below it and the lobes of the open corolla.

One of the defining characteristics of the members of the larger Tomato family is that they all produce alkaloids, though those of the Petunioideae tend to be less toxic, (With exceptions!  There are always exceptions!) less psychoactive or even therapeutic as medicines.

Erica mammosa, one of the larger flowered South African Heaths, exhibiting its typical 4 petal, fused corolla tubes. Their calyxes at the base, greenish, include 4 sepals. The inflorescence is spike like with each flower attached by a short peduncle to the stem at a leaf axil forming an overall whorled structure. Plants often defy our expectations. The genus Erica, which here in the PNW we tend to think of as a northern temperate group, because that is where most of the plants we garden with come from, includes 580 species native to South Africa…520 of which are endemic there, generally to very small areas.

Here you can see the exserted stamen of an Erica nevillei flower with the 4 flaring lips of the petals that comprise the fused, tubular, corolla

This is Erica nevillei. Dissected to show its floral parts you can see the long fused flower tube with the very short green calyx at the base which contains the small, superior, ovary. In flowering plants like these with a superior ovary, both the calyx and corolla enclose the ovary, though their forms can vary considerably.

….Remember those very similar looking South African Erica species?  They too are in the Asterids, but are very different genetically.  They’ve taken their own unique genetic material and evolved a very similar form.  There are other forces lurking behind the way a plant looks and functions than its ‘simple’ genetics.  There are multiple ‘patterns’ that have proven successful and different plants, in different parts of the world have successfully replicated them, in their own unique ways mixing ‘features’ sometimes found on widely disparate species….In this case Erica and Fabiana share their fused, floral tubes, each structured slightly differently.  In Erica they are made up of 4 rather than the 5 petals of Fabiana, differing also with their 4 sepals making up the shorter calyxes of Erica spp.  They share the superior ovary characteristic, but many of the tiniest details vary and are brought together in a different way.  Erica flowers also have 4 stamen which tend to extend just beyond the mouth of the open corolla…unlike those of Fabiana, which have 5 that do not extend beyond the corolla.  None of this seems terribly obvious or helpful in separating them from one another…but it’s not supposed to be.  Life is simply following larger successful patterns in individual ways, patterns that themselves are evolving over time, into forms of greater richness and complexity…building.  Familiarity with the two genera, their overall habit and appearance, including the small details, their native ranges and growing conditions altogether show them as distinct…but it is true that plants are often quite difficult to tell apart, as plants share much more amongst themselves than they hold uniquely.  Such is the way of genetics and evolution.

Other Cousins

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Cestrum x ‘Orange Peel’ taken in early November. I have grown this plant successfully here in Portland for a number of years without making any undue effort to protect it.This plant can bloom heavily and steadily here for 6 months plus for me, depending on how hard it was frozen back in the preceding winter and how much of its previous years growth has to be replaced. In contrast the Fabiana has a much shorter flowering season limited to early summer.  You can also see the difference in the structures of their inflorescence with the Cestrum flowers held in an open panicle.

Cestrum is another closely related genus of the Tomato family with over 150 different species of very similarly structured tubular flowers, most of which are native to South and Central America, with a few found in the southern US.  Cestrum are, however, in another sub-family, so a little more genetically distant, the Cestroideae, one of the sisters of Petunioideae (All sub-family names end in the suffix ‘oideae’).  Cestrum is the largest genus within its sub-family. Their genetics have them evolving similar structures along independent lines.  Cestroideae can be further divided into four different ‘tribes’, with a total of only ten genera between them.  Included with them are the six Browallia species of the tribe Browallieae, Salpiglossis sinuata and S. spinescens natives of southern Chile, are included in the tribe Salpiglossideae, while the Benthamiella spp. a genus of compact cushion plants, limited to Patagonia, form most of the tribe Benthamielleae.  The four genera pictured below are representative of each of their tribes.  It requires a critical eye to separate all of these into assigned classifications, but the physical differences are there and they are supported by their genetics.

Cestrum parqui has the long narrow tube of Fabiana and shares much of its range north and south is limited to the coastal mountains of Chile.  Its green calyx encloses from 1/3-1/2 of the flower tube.  Cestrum parqui, which I haven’t grown, shares much of its Chilean range with Fabiana imbricata, but is more limited in elevation and is found lower in the coastal mountains.

Benthamiella patagonica a genus of compact cushion plants from the extremes of Patagonia includes 12 species and is a member of the tribe Benthamielleae….You’ve gotta love this plant!

The Jamaican forget-me-not, amethyst flower, or bush violet (Browallia americana) is native to tropical Latin America, from Mexico and the Caribbean, south to Peru and Brazil. Its broad, open-faced lobes contrast with its narrow tube. The flower pictured from its side show its long narrow tube.

Painted Tongue Velvet Dolly Mix (Salpiglossis sinuata) has a broader,more open funnel narrowing down to the ovary at the bottom.  The species also has a wide color range which caught the attention of breeders.  One of the limiting factors in this plant’s ‘garden’ success is that its natural range is limited to the cool/wet region of southern Chile, which in turn limits its use in hotter gardenss.  This is the most commonly utilitized plant in the Cestroideae in the garden world with many cultivars.

 

 

 

Here is an alternative description for Fabaina imbricata.

As gardeners we will only ever know a relative few of the many thousands of plants that have evolved on and populate the Earth.  It is invaluable for us to have some understanding of their diversity and complexity, as well as of the relationships that they share between them and the worlds other organisms.  We as gardeners and global citizens, must act ‘rightly’ by them, protecting the world for them, so that they can complete their necessary roles in maintaining the systems that make life possible, thereby insuring that there is a healthy world for ourselves, our children and for those who will follow us.  The world is truly a fantastical place and we must do what we can to honor, support and defend it!

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